package com.goods.management.controller;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

/**
 * 请求拦截器，处理跨域问题
 *
 */
public class CommonInterceptor implements HandlerInterceptor {

	private List<String> excludedUrls;

	public List<String> getExcludedUrls() {
		return excludedUrls;
	}

	public void setExcludedUrls(List<String> excludedUrls) {
		this.excludedUrls = excludedUrls;
	}

	/**
	 *
	 * 在业务处理器处理请求之前被调用 如果返回false
	 * 从当前的拦截器往回执行所有拦截器的afterCompletion(),
	 * 再退出拦截器链, 如果返回true 执行下一个拦截器,
	 * 直到所有的拦截器都执行完毕 再执行被拦截的Controller
	 * 然后进入拦截器链,
	 * 从最后一个拦截器往回执行所有的postHandle()
	 * 接着再从最后一个拦截器往回执行所有的afterCompletion()
	 *
	 * @param  request
	 *
	 * @param  response
	 */
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
									 Object handler) throws Exception {
		response.setHeader("Access-Control-Allow-Origin", "*");
		response.setHeader("Access-Control-Allow-Methods", "*");
		response.setHeader("Access-Control-Max-Age", "3600");
		response.setHeader("Access-Control-Allow-Headers",
				"Origin, X-Requested-With, Content-Type, Accept");
		return true;
	}

	// 在业务处理器处理请求执行完成后,生成视图之前执行的动作
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
								  ModelAndView modelAndView) throws Exception {

	}

	/**
	 *
	 * 在DispatcherServlet完全处理完请求后被调用
	 * 当有拦截器抛出异常时,
	 * 会从当前拦截器往回执行所有的拦截器的afterCompletion()
	 *
	 * @param request
	 *
	 * @param response
	 *
	 * @param handler
	 *
	 */
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
										 Object handler, Exception ex) throws Exception {

	}
}

